Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.I would start first with checking the computer system scanned to see if there are any fault codes and or codes setting , I would also install a fuel pressure and monitor the fuel pressure while the lack of power is present. Check these two thing for me and post back with the results and we can work from there.